Rheumatoid arthritis (RA) is an autoimmune disease which causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Because it can affect multiple other organs of the body, rheumatoid arthritis is a systemic illness and is sometimes called rheumatoid disease. Rheumatoid arthritis is a chronic disease, mainly characterized by inflammation of the lining, or synovium, of the joints. It can lead to long-term joint damage, resulting in chronic pain, loss of function and disability.
RA can start in any joint, but it most commonly begins in the smaller joints of the fingers, hands and wrists. In general, more joint erosion indicates more severe disease activity. RA progresses in three stages. The first stage is the swelling of the synovial lining, causing pain, warmth, stiffness, redness and swelling around the joint. Other common physical symptoms include fatigue, weakness, pain associated with prolonged sitting, occurrence of flares of disease activity followed by remission, rheumatoid nodules (lumps of tissue under the skin, typically found on the elbows), and muscle pain. Second is the rapid division and growth of cells, or pannus, which causes the synovium to thicken. In the third stage, the inflamed cells release enzymes that may digest bone and cartilage, often causing the involved joint to lose its shape and alignment, more pain, and loss of movement.
Because it is a chronic disease, RA continues indefinitely and may not go away. Frequent flares in disease activity can occur. Early diagnosis and treatment of RA is critical to living a productive lifestyle. Studies have shown that early aggressive treatment of RA can limit joint damage, which in turn limits loss of movement, decreased ability to work, higher medical costs and potential surgery. Currently, the characterization of a disease condition related to RA (including diagnosis, staging, monitoring disease progression, monitoring treatment effects on disease activity) is imprecise. There is no one test which positively indicates a subject has RA. A diagnosis typically is made from a combination of the following procedures and tests: a medical history; a physical exam looking for common features reported in RA including but not limited to joint swelling, joint tenderness, loss of motion in the joints, and joint malalignment; signs of RA in other organs including but not limited to skin, lungs and eyes; lab tests, including but not limited to measuring blood cell count, erythrocyte sedimentation rate (ESR), C-Reactive Protein levels, Rheumatoid Factor, and Antinuclear Antibodies; and imaging studies, including but not limited to X-rays, magnetic resonance imaging (MRI), joint ultrasound, and bone densitometry (DEXA). Thus a need exists for better ways to diagnose and monitor the progression and treatment of rheumatoid arthritis.
Several therapeutic options exist for the treatment of RA. The major goals of therapy are to relieve pain, swelling, and fatigue, and to improve joint function, stop joint damage, and prevent disability and disease related morbidity. Treatment of the disease may involve a combination of two or more therapeutics compounds, including non-steroidal anti-inflammatory drugs, (“NSAIDs”, e.g., ibuprofen), COX-2 inhibitors (e.g., celecoxib (Celebrex)), low dose corticosteroids, disease-modifying anti-rheumatic drugs (“DMARDs”, e.g., methotrexate, leflunomide, gold thiomalate, aurothioglucose, or auranofin), Tumor necrosis factor (“TNF”) inhibitors (e.g., etanercept (Enbrel), infliximab (Remicade), and adalimumab (Humira), interleukin-1 inhibitors (e.g., injectible anakinra (Kineret)), and other biologic response modifiers (“BRMs”). However, careful monitoring of DMARD and BRM is essential to treatment. Information on any condition of a particular patient and a patient's response to types and dosages of therapeutic or nutritional agents has become an important issue in clinical medicine today not only from the aspect of efficiency of medical practice for the health care industry but for improved outcomes and benefits for the patients. Thus, there is the need for tests which can aid in the diagnosis and monitor the progression and treatment of RA.